Standard is the best for single target and well-clumped aoe. Destro ult is better for bursting down more spread out adds, like vSO or vMoL trash pulls. Also good to use when you know you'll have to move soon, like for killing early adds in Warrior hardmode or pad 0 on Rakkhat. The aoe alone from the Standard actually does close to the same total damage as the destro ult, though it takes twice as long to eek out. And the +15% outgoing -15% incoming damage makes it standard (lel) for any standard (lel) boss fight. I personally run destro front standard back anyway since I backbar blockade and need the ult front for the Ancient Knowledge passive, so I can always decide which will be better in the moment.


Side note, for cheesing a 3m dummy parse I actually go meteor front standard back, with the meteor used as second ult, just because it works out better with the current mdk ceiling and having my own eledrain slotted front for the destro passive.

I tend to use Standard more for single target (bosses who are kept more in place) or clumped up adds and Destro ult for more spread out adds.